Coupling device for multi-spring snap action electric switches



April 1959 E. c. CONNELLY 2,884,503

COUPLING DEVICE FOR MULTI-SPRING SNAP ACTION ELECTRIC SWITCHES FiledJan. 21, 1958 II ulnar-f 1 27 INVENT OR.

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United. States Patent COUPLING DEVICE FOR MULTI-SPRING SNAP ACTIONELECTRIC SWITCHES Eugene C. Connolly, Chicago, IlL, assi or to Electro-Snap Switch & Mtg. (10., Chicago, ll a corporation of IllinoisApplication January 21, 1958, Serial No. 710,262

7 Claims. (Cl. 200-172) This invention relates to snap action electricswitches having a plurality of bridging contact springs operatedsimultaneously by a single operating button and has for a principalobject the provision of a new and improved switch of this type. I

It is a main object of the invention to provide a new and improvedcoupling device for connecting the operating button of an electricswitch to the spring link assembly, by which the plurality of contactcarrying springsof the switch are operated by an operation of theoperating button.

Another object of the invention is to provide a coupling device whichinsures positive drive action between the operating button and springlink assembly of a multispring snap action electric switch.

Another object of the invention is to provide a coupling device whichcan be manufactured and assembled at low cost without sacrificingquality.

Further objects of the invention not specifically mentionedhere will beapparent from the detailed description and claims which follow,reference being had'to the accompanying drawings in which a preferredembodiment of the invention is shown by way of example and in which:

Fig. 1 is a side elevational view of a switch embodying the invention,drawn to an enlarged scale;

Fig. 2 is a front elevational view of the switch of Fig. 1, with thecover removed from the casing;

Fig. 3 is an exploded view in perspective of the yoke and part of thespring link assembly of the switch;

Fig. 4 is a rear elevational view of the operating button; and

Fig. 5 is a side view, partly in section, of the operating button, yokeand spring link assembly of the switch.

Multi-spring electric switches of the snap action type are usuallyencased in a casing composed of an insulating material and from whichcasing an operating button is projected. Within the casing, contactcarrying bridging springsare connected together by a spring linkassembly which mechanically couples together the compression tongues ofthe springs while maintaining the same electrically independent each ofthe other.

In prior art switches of this type, of which I am aware, the operatingbutton has been connected to the spring link assembly by means of a pincarried by the button and projecting through a slot in a metallic endmember of the assembly which projects into a cavity in the button. Inother instances, a plungerlike head on the end of the link assembly isprojected into a cavity in the button and a spring made to bear againstthe plunger to cause movement of the button to move the spring linkassembly.

The present invention provides a new and improved arrangement forcoupling the operating button of a switch or this type to the springlink assembly thcreof. In its preferred form the coupling device of thepresent inventionconsists of a metallic yoke fixed in a cavity in the31110011. projecting from the button-and eontaining-perfora- 2,884,503Patented Apr. 28; 1959 "ice tions through which a metal end piece on thespring link assembly is projected, that end piece containing slots intowhich the yoke projects to secure the yoke to the link assembly. Throughthis arrangement a positive drive con- 5 nection is established betweenthe operating button of the switch and the spring link assembly by whichthe bridging springs of the switch are moved to overcenter position.This positive drive insures that after slack has been taken up, eachincrement or movement of the operating button produces a like incrementof movement of the link assembly, thereby permitting more accurateadjustment of the switch with respect to the position-of the operatingtton at the momentgthe bridging springs overccnter.

a panying drawings in which in Figs. 1 and 2- a multi-spn snap actionswitch of known design is shown, this switch consisting of a casing 1composed of an insulating material and having within it two or moretransverse cavities 2, in'each of which contact bridging spring 3 islocated. The casing also contains a cavity 5 in which the spring linkassembly 6 is positioned and contains a perforation 7 through which theoperating button 8 projects. In the switch shown by way of example,there are three bridging springs 3, each of which is of knownconstruction having outer tension arms connected together at their endsby contact carrying end portions, from which end portions centrallylocated compression tongues extendtowards the center of the spring.

As will be seen in Figs. 3, 4 ands, the coupling device of the presentinvention consists of a yoke 10 having an endwall 11 that contains arectangular slot 12. Generally rectangular arms 13 project from thesides ofthe end wall 11 andcontain near, their outer ends cars 14 bentout of the arms 13, and increasing the effective thickness of thesearms.

The spring link assembly 6, which is of known design, consists ofinsulating members 15 which in a 3-spring switch are two in number,connected together by a mew tallic member 16 that contains a perforation17 into which the compression tongues of the central bridging spring areprojected. The link also contains a similarend member 18 and a secondend member 19, to which'latter member the present invention particularlyrelates.

As will be seen in Figs. 3 and 5, the end member 19 contains atonguelike portionZt), a perforation 21 into which the compressiontongues of one of the bridging springs lit, and rectangular slots 22opening into the edges of the member. The inner ends of the slots 22define between them a neck portion 23 having width transversely of themember 19 slightly less than the width of the slot 12 in the yoke.

As will be seen in Fig. 5, coil spring 24 encircles the insulatingmember 15 adjacent the end piece 19.

as In assembling the link onto the yoke, end piece 19 is insertedthrough the rectangular slot 12 and then turned through 90' to positionthe portions of the end wall 11 of the yoke alongside of the slot 12into the slots 22 in the member 19. The coil spring 24 is thus abutted60 against the end wall 11 of the yoke.

AswillbeseenbestinFigs.4and5,theoperating button8 eontainsa rearfacezsinto whichopeos acavity having a central portion 26 and transverselydisposed end portions 27. the cavity being generally I-shape in crosssection. 'lhebuttouflisprovidedwithflangesflwhlch transverselydisposedslots 27 andtheendportionztloftheeudpieceflrc'gisteredwithflrecsntralportlon 26 of the cavity. Thecentral portion 26 of the cavity has invention will be bestunderstood byreference to" width greater than the thickness of the tongue portion 20of the end piece 19, with the result that the tongue loosely fits intothe cavity. The transversely disposed end portions 27 of the cavity havethickness less than the effective thickness of the arms 13 produced bythe outwardly extending cars 14, and as a result these arms 13 must beforced into the cavity portions 27 and the cars 14 thereby moved towardsalignment with the arms 13 out of which they project. Yoke beingcomposed of half hard material, the arms 13 and cars 14 exertconsiderable pressure on the walls of the cavities 27. This arrangementsecurely attaches the yoke to the button.

While the width of portion 26 of the cavity in the button is greaterthan the thickness of the tongue 20, it is not suliicient to permitrotation of the tongue. Thus when the tongue is positioned in the cavity26, rotation of the button and yoke with respect to the spring linkassembly is definitely prevented. This insures that the portions of theyoke projecting into slots 22 will remain therein and the yoke willremain attached to the spring link assembly.

It will be noted that the depth of the cavity in the button is less thanthe length of the arms 13 of the yoke, with the result that when theyoke is fully installed in the button cavity with the ends of the yokeabutting against the inner end of the cavity, the end wall 11 of theyoke will be spaced from and substantially parallel to the rear face 25of the button. It will also be noted that the perforation 21 in the endpiece 19 is disposed between the end wall 11 of the yoke and the-rearface 25 of the button.

After the yoke has thus been assembled on the spring link assembly andattached to the button, the bridging springs 3 are attached thereto,each with its compres sion tongues registered with one of theperforations such as .17 or 21 in the metallic portions of the link. Itwill be noted that the casing 1 contains shoulders 9 that project intothe cavity 5 of the casing. When the springs, the link, yoke and buttonare inserted in the casing, the end of the coil spring 24 remote fromthe yoke is abutted against the ears 9 and the spring is compressedthcreby to urge the button 8 outwardly of the casing thereby to maintainthe flanges 28 on the button in engagement with the casing walls.Preferably the button 8 and the perforation 7 are of rectangular shapeand rotation of the moving parts'of the switch with respect to thecasing is prevented by engagement of thesides of the button with theedges of the perforation.

Assembly of the switch is completed by registering the cover 1A with thecasing 1 and securing it thereon.

To operate the switch, operating button 8 is moved inwardly of thecasing thereby to move the end wall 11 of the yoke into engagement withthe sides of the slots 22, in the end piece 19, that are remote from thebutton. Further movement of the button inwardly of the casing moves thelink assembly 6 through-the positive drive connection established by theen of the rear wall 11 of the yoke with the edges of the slots 22. Thismovement continues until the springs over-center, thereby to move thecontacts carried by these springs from their normally closed to theirrespective normally open stationary contacts.

If it is desired to provide for sinnlltaneous action of the plurality ofbridging springs 3 of the switch, slots22aremadewideraxiallyofthecpringlinkblythanthethicknessoftherear'walllloftheyoke.'lhroughthisamngemenaaseoonasoneofthebridging spring! 3 overcenters, thespring link assembly moves aheadofthe yokeandtheremainingbridglngsprings 3 are thereby overcentered and simultaneousactionis achieved. Inlnsta'nceswheresimultancous actionisnotdesired,-thewidthoftheslots zzisnarrowedtolliahtly morethanthe thicknessoftherearwalllloftheyoke andnosuchfreemovement ofthcspringlink assemblyresults.

When operating pressure is removed from. the button 8, spring 24 bearingagainst the wall 11 of the yoke 10, moves that wall into engagement withthe edges of slots 22 adjacent the button, then moves the spring link 6and the button 8 to normal positions, with the flanges 28 on the buttonengaging the walls of the casing. Springs 3 are overcentered by thismovement returning the contacts carried thereby to their respectivenormally closed stationary contacts.

From the foregoing, it will be apparent that the coupling device of thepresent invention possesses many advantages. It is of simpleconstruction and can be assembled easily, at low cost, withoutsacrificing quality. Should occasion arise, the coupling device can bedisassembled easily and without mutilation or destruction of any of theswitch parts.

While I have chosen to illustrate my invention by showing and describinga preferred embodiment thereof, I have done so by way of example only,as there are many modifications and adaptations which can be made by oneskilled in the art within the teachings of the invention.

Having thus complied with the statutes and shown and described apreferred embodiment of my invention, what I consider new and desire tohave protected by Letters Patent is pointed out in the appended claims.

What I claim is:

1. In a multi-spring electric snap switch, a spring link assembly; anoperating button having a rear face into which a cavity of I sectionopens; a metal member projecting from the end of the spring linkassembly and projecting into the central portion of the cavity in thebutton, said metal member having slots opening into its opposite edges;and a U-shaped metal yoke the closed end of which contains a slotthrough which said metal member projects, said closed end projectinginto the slots in said metal member and the arms of said yoke extendinginto the transversely disposed end portions of said cavity thereby toconnect the button to the link assembly.

2. In a multi-spring electric snap switch: a spring link assembly; anoperating button having a flat rear face into which a cavity of Isection opens; a flat metal member projecting from the end of the springlink assembly and projecting loosely into the central portion of thecavity in the button, said metal member having slots opening into itsopposite edges; a metal yoke having an end wall containing a rectangularslot through which said flat member projects, the portions of said endwall adjacent said slot projecting into the slots in said flat metalmember to attach the yoke to the spring link assembly; and parallel armson said yoke extending at right angles from the ends of said end walland into the transversely disposed end portions of said cavity to attachthe button to the yoke.

3. In a multi-spring electric snap switch, a spring link assembly; anoperating button having a rear face into which a cavity of I sectionopens; a flat metal member projecting from the end of the spring linkassembly and projecting loosely into the central portion of the cavityin the button, said metal member having slots opening into its oppositeedges; 0. metal yoke havinganendwallcontainingarectangularslotthroughwhich said flat memberprojects, the portions of said end wall adjacent said slot projectinginto the slots in said flat metal member to attach the yoke to thespring link assembly; parallel arms on said yoke extending at rightangles from the ends of said end wall and into the transversely disposedend portions of said cavity; and cars extending outwardly of said armsand frlctlonally portionsofthebuttondefiningtheeavityto secure thebutton on the yoke.

4. In a mold-spring electric snap switch, a springlinkassemblmanoperatingbuttonhavingaflatrear facerntowhlehncavltyoflsectionopensraflatmetal member projecting from theend of the spring link assembly and projecting loosely into the centralportion of the cavity in the button, said metal member havingrectangular slots opening into its opposite edges the inner ends ofwhich slots defining a neck portion of the member; a metal yoke havingan end wall containing a rectangular slot through which said neckportion projects, with the portions of said wall alongside saidrectangular slot disposed in said slots to attach the yoke to the springlink assembly; and parallel arms on said yoke extending at right anglesfrom the end of said end wall and into transversely disposed endportions of said cavity to attach the button to the yoke.

5. In a multi-spring electric snap switch, a spring link assembly; anoperating button having a flat rear face into which a cavity of Isection opens; a flat metal member projecting from the end of the springlink assembly and extending loosely into the central portion of saidcavity, said metal member having slots opening into its opposite edges;a metal yoke having a flat end wall containing a rectangular slotthrough which said flat member projects with the portions of the endwall alongside said slot extending into the slots in the metal member;rectangular parallel arms projecting from the ends of said end wall atright angles thereto, the faces of said arms being disposed at rightangles to the faces of said flat metal member, said arms extending intothe transversely disposed end portions of said cavity to attach thebutton to the yoke, with said flat end wall disposed parallel to andspaced from said flat rear face on the button.

6. In a multi-spring electric snap switch, a spring link assembly; anoperating button having a flat rear face into which a cavity of Isection opens; a flat metal member projecting from the end of the springlink assembly and projecting loosely into the central portion of thecavity in the button, said metal member having slots opening into itsopposite edges; a metal yoke having an end wall containing a rectangularslot through which said flat member projects, the portions of said endwall adjacent said slot projecting into the slots in said flat metalmember to attach the yoke to the spring link assembly; parallel arms onsaid yoke extending at right angles from the ends of said end wall andinto the transversely disposed end portions of said cavity; earsextending outwardly of said arms and frictionally engaging portions ofthe button defining the cavity to secure the button on the yoke; acasing for said switch, there being a cavity in said casing and aperforation therein aligned with said cavity, said spring link assemblybeing disposed in said cavity and said button projecting out of thecavity through said perforation; flanges projecting laterally from saidbutton and engaging said casing adjacent said perforation; shoulders insaid cavity facing said perforation; and a spring encircling said springlink assembly and abutting against said shoulders and the yoke toyieldingly hold said flanges against the casing.

7. A device for coupling an operating button to the spring link assemblyof a multi-spring electric switch comprising: a metallic yoke ofgenerally U-shape having a perforation in its closed end; a flat endmember on said spring link assembly projecting through said perforation,said end member containing slots opening into its edges, into whichslots portions of the closed end of the yoke project to attach the yoketo the assembly; said button containing a cavity into which the endmember projects, the walls of said cavity preventing rotation of the endmember with respect to the yoke thereby to prevent detachment of theyoke from the end member; and said button containing cavities into whichthe arms of the yoke snugly fit to fix the button upon the yoke.

References Cited in the file of this patent UNITED STATES PATENTS2,106,581 Unwin Jan. 25, 1938 2,376,403 Thompson May 22, 1945 2,750,463Roeser June 12, 1956 2,815,420 Meyer Dec. 3, 1957

